Drop Pipe Choice With New Pump

I'm out of town (of course) and my wife calls saying there is no water. I'll get dad to go over and test and see what we can find out, but I don't have a good feeling.

Assuming I need a new pump, what do you recommend for drop pipe? 4" pvc casing, 80-120' deep (probably 80'), 1/2 HP pump currently on galvanized pipe. Some sulfur and iron in water. I've seen a couple new wells recently put in with pvc drop pipe and this seems a good way to go. What type of pipe and couplings are best? Thread sealant? How tight? I appreciated any and all advice!

Also, on the CSV, would I put one in the well or above ground near my pressure tank?

I like polyethylene pipe with brass or stainless steel adapters. We ran pumps as deep as 400 feet on a good grade of 1" polyethylene pipe in Northern Pennsylvania and it worked fine. PVC is OK but always an effort to pull. I'd use an adjustable (not plastic) CSV valve near the tank.

160 lb poly will support the weight of the pump ok, but it is super flexible and the wire will get chafed up big time unless there are plenty of torque arresters installed. Another problem is that when you have to pull poly, it lays on the ground and can pickup all kinds of bacteria and transfer the bacteria to the well.

For future reference though, I've pulled pumps on poly before but they had a rope/cable holding the weight. I know most here prefer to not use a rope and that is fine, but how do you anchor the poly at the well seal to hold the weight?

Also, we've just taped the wire to the poly and never had a problem with it rubbing through with no torque arrestors, etc. Is this just luck or the way it should be done?

In most areas code says you need a rope or a wire. In truth though, it's not like anybody is ever going to check that. Personally having used rope over the years I can honestly say that it's a waste of time and money. Theres no way in hell you are going to pull a pump 300 plus feed with quarter inch rope.